This invention relates generally to the manufacture of phosphoric acid or triple superphosphate from phosphate rock and relates more particularly to the wet grinding of crude phosphate rock for use in such manufacture.
In many deposits of rock phosphate, the basic material occurs in natural combination with various quantities of clay minerals which include impure hydrated aluminum silicates. These latter have been found to produce adverse effects in wet grinding procedures and in subsequent transport of the pulverized rock in the form of a water slurry.
It has been proposed heretofore to incorporate surfactants into the ground rock slurry either before or after it leaves the grinding mill in order to facilitate pumping. However, effective levels of such surfactants contribute unacceptable cost disadvantages and may possibly interfere with gypsum crystal formation during subsequent acidulation of the slurry.
Therefore, an important object of the present invention is to provide an economical method of improving the processability of a phosphate rock slurry having a high clay content.
A more general object of the invention is to provide a new and highly advantageous method of fluidizing rock slurries.
Another object of the invention is to provide a procedure for wet grinding phosphate rock wherein the resultant slurry has enhanced fluidity.
Still another object of this invention is to provide a method of wet grinding crude phosphate rock which permits subsequent handling of rock slurries of higher than normal rock solids content.
These and other objects and features of the invention will become more apparent from a reading of the following descriptions, relating specifically to the wet grinding of phosphate rock but to which the application is not to be restricted.